In multicast and broadcast applications, data are transmitted from a server to multiple receivers over wired and/or wireless networks. A multicast system as used herein is a system in which a server transmits the same data to multiple receivers simultaneously, where the receivers form a subset of all the receivers up to and including all of the receivers. A broadcast system is a system in which a server transmits the same data to all of the receivers simultaneously. That is, a multicast system by definition can include a broadcast system.
As used herein the term “client” includes but is not limited to stations, client stations, mobile stations, mobile terminals, mobile devices, nodes, laptop computers (laptops), notebook computers (notebooks), personal digital assistants (PDAs), dual mode smart phones, iPhones, iPods, iPads, tablets or any other wireless devices that can be connected to a network.
With multiple clients connected to a wireless router, gateway or access point (AP), ideally all clients would be connected with high link quality so high rate modulation schemes can be used. In this case, each client utilizes a short duration of time to transmit or receive data. If one client, however, has poor connection quality, a low-rate modulation scheme must be used. A low or lower-rate modulation scheme means that a longer time will be needed to transmit or receive an equivalent amount of data. As such, the client with poor link quality (a poor connection) will require a disproportionate amount of the available time for its communication, leaving reduced channel capacity for the remaining clients with good link quality (a good connection).
Various Quality of Service (QoS) mechanisms are known in the prior art but these QoS mechanisms are based on service quality categories that are setup in advance. None of these QoS mechanisms specifically address the issue of WiFi congestion as a function of link quality.